Diagnosing patients referred for hypoglycemia

This year I have seen a few patients referred for “hypoglycemia.” Each presented with a long history (>12 months) of symptoms of feeling faint or light headed, usually associated with sweating or flushing, and always relieved within 10 to 15 minutes by a glass of orange or apple juice. Two of the patients had undergone a five-hour glucose tolerance test during which they had a blood glucose level in the low 60s at hour three or four, but did not have any symptoms at those times. None of the patients reported being awoken by these symptoms nor having symptoms in the fasting state.

After completing a history and physical examination and unable to come up with a good working diagnosis, I have sent the patients home with a new blood glucose meter, instructed them how to use it, and requested that they check their capillary blood glucose any time they have a recurrence of symptoms. Of course they need to check CBG before their glass of juice. Not a single one of them has recorded a CBG of 70 mg/dL or lower associated with their symptoms. None of them have a fasting CBG 100 or higher. Remember, testing with a glucose meter is not as good as a laboratory glucose measurement, but this latter is hard to obtain unless the patient can be near a blood drawing facility at the time of symptoms.

What is this syndrome? I believe the symptoms, including recovery with juice, are real, but I doubt it is related to the CBG. None had postural hypotension, electrolyte abnormalities or lab values suggestive of pheochromocytoma. “Panic attacks?” Maybe, but there has been no apparent precipitating factor.

Frequent small meals may decrease the occurrence of episodes in some patients, but the evidence to support this approach is limited. Provided the frequent meals are indeed small and don’t result in weight gain, this seems a reasonable solution.